US3028866A - Machines for manipulating cut tobacco - Google Patents

Description

April 10, 1962 D. w. MOLINS MACHINES FOR MANIPULATING CUT TOBACCO 4 Sheets$heet 1 Filed Dec. 26, 1957 INVENTOR ATTOR/VE Y8 April 10, 1962 D. w. MOLINS MACHINES FOR MANIPULA'I'ING CUT TOBACCO 4 Sheets-Sheet 2 Filed Dec. 26, 1957 INVENTOR BY M @& Z4142; @122 A TTO/Q/VEX;

April 10, 1962 D. w. MOLINS 3,028,855

MACHINES FOR MANIPULATING CUT TOBACCO Filed Dec. 26, 1957 '4 Sheets-Sheet s IN VEN 7 OR ATTORNEX;

A ril 10, 1962 D. w. MOLINS 3,028,866

MACHINES FOR MANIPULATING CUT TOBACCO Filed Dec. 26, 1957 4 Sheets-Sheet 4 A TTORNE United States Patent Ofiiice 3,028,866 Patented Apr. 10, 1962 This invention concerns improvements in or relating to machines for manipulating cut tobacco, for example, cigarette-making machines. In tobacco manipulating machines, cut tobacco is fed and many subsequently issue from the machine in separated portions, e.g. as cigarettes in a cigarette-making machine or as packages in a tobacco packaging machine.

In such tobacco manipulating machines cut tobacco is removed from a mass and spread in some way on a conveyor which carries it as a continuous stream or filler through or towards devices which manipulate it to form it into a continuous tobacco rod which may eventually be enclosed in a continuous paper wrapper, The bestknown example of such a machine is the continuous rod cigarette-making machine.

Cigarette-making machines of the continuous rod type are provided with tobacco-feeding apparatus in which a mass of cut tobacco is placed in a hopper and subjected to various brushing and combing operations and finally showered on to a conveyor, where it forms a loose tobacco filler, and by means of which, or of a succeeding conveyor, it is formed into a tobacco rod or core which is afterwards wrapped in paper.

The aforesaid loose filler and the resulting rod are not as uniform in consistency as is desirable, and many attempts have been made to improve the uniformity of distribution of the tobacco in the final rod. To a great extent this defective distribution in the tobacco filler is no doubt due to irregularities in the shower itself, but it is believed that it is also caused to a considerable extent by events taking place as the shower contacts with the conveyor on to which it falls. This conveyor always moves at a high speed, i.e. at least at a speed equal to a rod speed giving 1000 cigarettes per minute of 70 mm. cigarette length.

The shower is usually long and narrow in cross-section and the conveyor that receives the shower is often arranged horizontally so that considered in the direction of movement of the conveyor the tobacco falls at right angles thereto. It has long been realized that in such an arrangement, when the conveyor moves fast (as in modern highspeed cigarette manufacture) a falling tobacco particle striking the fast-moving conveyor tends to rebound and, being unable to change its motion instantaneously to that of the conveyor, tends to fall back on to some part of the conveyor other than that on which it originally fell. This displacement of rebounding tobacco particles lengthwise of the conveyor is itself irregular and thus results in irregular distribution of tobacco along the length of the stream formed on the conveyor. Various proposals have been made, in an endeavour to overcome this difiiculty, for means to give the falling tobacco a component of movement in the direction of movement of the conveyor.

In a case such as that just referred to, the falling tobacco particles are, relatively to the conveyor, moving rearwardly at an acute angle to the conveyor surface. If the upper surface of the tobacco already on the conveyor has an irregular or wavy contour, the higher portions of the semi-formed stream will tend to intercept falling tobacco particles, with the result that tobacco will tend to pile up on or in front of such higher portions while the lower portions will be to some extent shielded by the high portions and thus not receive as much tobacco as they otherwise would, In this way the irregularity already existing (due to irregular bouncing of the tobacco or to any other cause) is aggravated. Even if the upper surface of the tobacco is regular, however, there will almost certainly be shreds of particles projecting upwardly from the stream above the general level of the surface, which upstanding shreds will act, in the same way as described above with reference to high portions of the stream, to cause piling up of the falling tobacco at irregular intervals.

Mention has been made of irregularities in the shower itself. These may be caused by irregularities in the layer or carpet of tobacco from which the tobacco showered on to the conveyor is picked. It is believed, however, that they may also in part be present in a case where tobacco, when picked from the carpet, is not thrown downwardly directly towards the conveyor but is thrown upwardly, for the purpose of winnowing it, and then drops on to the conveyor after stalk and other heavy particles have been taken out.

According to the invention there is provided a method of forming a filler in a tobacco manipulating machine wherein tobacco is showered on to a slow moving conveyor moving lengthwise of the shower to form thereon a stream or carpet whose volume per unit length is several times the volume per unit length of the final filler, said stream being manipulated to average its inequalities as far as possible to provide a stream more uniform than the stream as showered, the manipulated stream being then transferred endwise to a faster moving conveyor and the relative conveyor speeds being such that the stream on the faster conveyor is of a volume per unit length of the order of the volume per unit length of the final filler. For example, the fast conveyor may be that on which the filler is formed to its final shape.

Manipulation of the first said stream may take place in various ways but is preferably elfected by feeding the stream into a passage from which it emerges at a slower speed than the speed of entry. An example of such manipulation is described in U.S. Patent 2,671,452, granted March 9, 1954, to this applicant and another.

As the stream in the present case contains a greater quantity of tobacco per unit length than is contemplated in the aforesaid patent, rearrangement of the stream by endwise compacting can (for a certain quantity compacted to a certain degree) take place over a shorter length of stream. This is considered preferable, as a compacting operation requiring a large endwise movement of tobacco to produce a certain quantity of compacted tobacco is not as satisfactory as a compacting operation giving the same quantity of compacting tobacco by a smaller endwise movement. Moreover, as the stream in the present case is formed as a carpet, that is, a wide and relatively shallow stream, it is possible for tobacco to move'about laterally as well as endwise or, at least, the tobacco has more freedom for lateral movement than in a narrow stream, As will be seen later in the example specifically described, 'manipulation takes place on a stream containing a quantity of tobacco per unit length about three times the quantity per unit length of. a cigarette filler.

Further according to the present invention there is provided in a tobacco manipulating machine (e.g. a cigarettemaking machine of the continuous rod type) a fast conveyor to receive tobacco and carry it lengthwise as a stream at high speed (e.g. at or above the speed of the cigarette rod), means to discharge tobacco (e.g. from a hopper) in the form of a shower, at slow conveyor arranged to move lengthwise of the shower at a slower speed than that of the said fast conveyor (e.g. at onethird the speed of the fast conveyor) to intercept the showered tobacco, said slow conveyor carrying the tobacco thereon into a passage having an entry of which said conveyor constitutes the bottom wall and having smooth faced side walls and a smooth faced top wall formed by an upper conveyor moving in the same direction as the slow conveyor but at a higher speed, the passage continuing beyond the delivery end of the slow conveyor with a bottom wall formed as a smooth plate, and transfer means to transfer tobacco from the outlet of the passage to said fast conveyor in such manner that the movement of the tobacco, as it reaches the said fast conveyor, has a substantial component in the same direction as the movement of the said fast conveyor. Preferably said component is so substantial that the tobacco reaching the fast conveyor is moving substantially at the speed of said conveyor.

The said transfer means may comprise picker mechanism to remove tobacco from the outlet of the passage and impel it at the desired speed and in the desired direction towards the said fast conveyor. Preferably the said fast conveyor is arranged at a lower level than the said slow conveyor. For example, it may be located beneath the slow conveyor, and may be arranged to run in the reverse direction to that of the slow conveyor. In the latter case, the direction of the tobacco will of course be reversed when it is transferred from the slow to the fast conveyor.

The transfer means may further comprise a toothed conveyor, for example a carded roller, on to which tobacco is fed from the outlet of the passage and from which it is picked by picker pins and thrown down on to the said fast conveyor in such a direction and at such a speed as to give the tobacco particles a component of movement as aforesaid on reaching the said fast conveyor. The transfer means may also comprise means, such as fan blades or vanes on the picker roller, whereby an air current is directed in the general direction of movement of the thrown tobacco so as to assist in imparting the desired speed and direction to said tobacco.

The said toothed conveyor may be arranged to move with a surface speed lower than that of the said slow conveyor and the speed of the tobacco at the outlet from the passage so that tobacco while being fed on to the toothed conveyor becomes packed into the teeth of the latter.

The said slow conveyor will of course be much more heavily loaded with tobacco than will the fast conveyor. To avoid forming an inconveniently deep stream, the slow conveyor is preferably made considerably wider than the fast conveyor. In such a case, means is provided to restrict the width of the path through which tobacco pmses from the slow to the fast conveyor. Preferably such means comprises converging guide walls to guide tobacco as it is thrown towards the fast conveyor.

It will be seen that where tobacco is showered on to a surface that moves lengthwise of the shower, the slower that surface moves the less will be the displacement of tobacco particles on it due to slipping and irregular bouncing as discussed above, and the less piling up will occur in front of upstanding tobacco shreds.

Moreover, where the shower itself is irregular (for whatever reason) the slower the surface moves the more likelihood there is of the unevenly showered tobacco becoming evenly distributed over the surface.

Thus the speed of the slow conveyor is preferably made as low as is reasonably practicable and convenient. This, however, is limited by the extent to which it is permissible to load the slow conveyor while enabling the tobacco to be transferred to the fast conveyor in a satisfactory way.

The slow conveyor may be arranged to slope downwardly in its direction of movement, and in that case it will be seen that vertically falling tobacco particles will have a component of movement in the direction of the conveyor and this may be made equal to the speed of the latter, which will further reduce the tendency of the falling particles to slip or to rebound irregularly on the slow conveyor.

Further according to the invention there is provided a method of forming a filler in a tobacco manipulating machine, comprising the steps of forming a. stream whose mass per unit length is at least a multiple of the mass per unit length required in the filler, feeding the said stream lengthwise into and through a passage in which its speed is reduced, whereby inequalities in the stream are reduced, and thereafter, while continuing the lengthwise feeding of the stream, accelerating it so as to reduce its mass per unit length to that required in the final filler. Preferably the said stream is formed by showering tobacco on to a conveyor whose speed is substantially less than the speed of the final filler.

Still further according to the invention there is provided, in a tobacco manipulating machine, apparatus for forming a filler, comprising means to form a stream whose mass per unit length is at least a multiple of the mass per unit length required in the filler (e.g. by showering tobacco onto a relatively slowly moving conveyor), a passage through which said stream is fed lengthwise, means to reduce the speed of the stream within the passage, means to continue the forward feeding of the stream and means to accelerate the tobacco during the continued forward movement of the stream so as to reduce its mass per unit length to that required in the filler.

Apparatus in accordance with the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIGURE 1 is a view partly in section looking at the root of a tobacco hopper of a cigarette-making machine and showing the collector conveyor and associated parts.

FIGURE 2 is a plan of the collecting conveyor of FIGURE 1.

FIGURE 3 is a section of FIGURE 1 on the line 3-3 and also shows part of the interior of the tobacco hopper.

FIGURE 4 is a diagram of the whole machine showing how the tobacco reaches the rod-forming mechanism.

FIGURE 5 shows a slightly modified construction of FIGURE 1.

FIGURE 6 is a section of FIGURE 1 on the line 6--6.

FIGURE 7 shows a modification to a picker roller.

FIGURE 8 shows another modification to a picker roller.

FIGURE 9 shows a modified arrangement of the collecting conveyor.

Referring to FIGURE 1, tobacco is showered down in the direction of the vertical arrows by devices shown in FIGURE 3 and falls on a slow conveyor consisting of a collecting conveyor belt 2. If desired this belt may slope downwardly in the direction of its movement as shown in FIGURE 9.

In FIGURE 3, 3 is a combining roller in a hopper 4, and 5 is a picking roller which picks tobacco from the carding on the roller 3. The picking operation takes place at the edge of a sloping plate 6, and the tobacco is forthwith thrown upwards at an angle by a winnower 7. Stalks and other heavy pieces are thrown over a partition, formed by a shield 9 and are thus separated from the tobacco and collected. Apart from the resulting and desirable separation of stalks and the like, the fall on to the slow conveyor is slower than if the picked tobacco were thrown down on to the said conveyor and this is advantageous.

The remaining tobacco partly slides down the shield 9, on to the belt 2, while some just falls freely on the belt. The shield 9 is canted with respect to the belt so that its bottom edge 9A, FIGURE 2, runs obliquely across the belt from one end to the other. That is, the far end, FIGURE 3, of the shield, corner 9B, is near one side of the belt while the near end, corner 9C, is near belt 2. At the side of the belt nearer the winnower' is a guide 8 so as to form with the shield 9 a passage for the tobacco falling towards the belt 2. Between the guide and the winnower the space is filled by a roller 8A, the roller being rotated so that tobacco or dust deposited thereon is transferred to the passage and thence to the belt.

The belt is about 3 or 4" wide whereas the width of the stream formed. on the hopper tape of an ordinary cigarette machine is say ll%" Wide, assuming that a flat stream is being formed. This means that the belt 2 can run at about one-quarter to one-third of the speed of a normal hopper tape and carry three to four times the tobacco per inch of length. With this substantial reduction of speed the disturbing effect of the contact between shower and collecting tape is very much reduced, and the tobacco lies on the belt in a manner which preserves the distribution achieved by the operations in the hopper and there is no accentuation of the distributional error. The showered tobacco then forms a wide carpet on the belt. At the right-handend of FIGURE 1, is a toothed or pin-roller 10 and to the left of this is a picker-roller 11. Tobacco is delivered to the pin roller as described later and pressed into the pin-roller by a smooth roller 10A. The pins 11A of the picker roller 11 are canted backwards as considered in the direction of rotation and this helps the picker roller to pick the tobacco from the pin-roller without appreciable breakage. The peripheral speed of the pin-roller 10 is less than the linear speed of the belt 2 so that a certain amount of packing action occurs during the transfer of tobacco from belt to pin-roller. Between the belt 2 and the pin roller 16 is a passage through which the tobacco passes from the belt to the pin roller but the description of this passage is deferred for the time being. A concave 12 surrounds the right hand side of the pin-roller and tobacco is picked at the edge 12A of the concave in the usual way. The picked tobacco is thrown down a chute 13 on to a second conveyor 14. This conveyor, see FIGURE 3, is narrow so its speed will be proportionately greater than that of the belt 2. Because it is narrow relatively to the belt 2, the chute 13 has converging side walls, see FIGURE 3. The picker roller 11 runs at a high speed and the tobacco is flung down the chute at a very high linear speed. It will be noted that the path of the shreds is at an angle (in the construtcion shown, 64) to the surface of the conveyor 14 and the speed of the shreds should preferably be such that if it is resolved into components parallel to the conveyor and at right angles thereto, the parallel component is substantially equal to the conveyor speed, so that there is no material tendency for the tobacco to slip on the conveyor 14, and particles which rebound will tend to return to the spot first struck. Further, any tendency for piling up in front of upstanding tobacco shreds is materially reduced. In this way transfer to the second conveyor is effected with a minimum of disturbance.

In order to assist in the desired transfer of tobacco from the pin roller 10 both as regards direction and speed, means for causing an air current may be provided, said current being directed in the general direction of movement of the thrown tobacco to help to impart the desired speed and direction thereto. Conveniently the current is caused by small vanes or blades 118, FIGURE 1, on the picker roller which is thus adapted to act as a fan. An alternative construction is shown in FIGURE 7 where picking is effected by wide blades 27 which also serve to produce the air current. on a plate and each blade picks tobacco from alternate spaces between the pins of the roller w. The succeeding plate has its blades 28 which are shown in broken lines I staggered with respect to the blades of the plate shown in full lines and picks tobacco from the spaces between the other pins.

In order to improve the picking operation, that is to attempt to improve its uniformity, the rows of the picker pins on roller 11 may be disposed helically, that is the pins form helices winding round and along the roller. With this arrangement, which is diagrammatically illustrated in FIGURE 8, only one picker pin is in line with the edge 12A of the concave at any moment and it is thought that this will be beneficial as it gives a continuous picking action.

The conveyor 14 may slope upwards in the direction of its movement to suit certain kinds of machines, for example, as will be seen in FIGURE 4, the conveyor 14 has to raise the tobacco to a position where it can pass into a smooth passage 15, of the kind described in copending Patent 2,671,452 aforesaid. At the bottom of this passage is a paper web 16 which carries the filler through the rod forming, sealing, and cutting devices of the kind commonly used on continuous rod cigarettemaking machines.

The above description covers the general construction and operation of the machine and devices for transferring tobacco from the slow conveyor 2 to the pinroller 10 will now be described. It will be seen from FIGURE 1 that the slow conveyor has its delivery end spaced some distance from the pin roller 10, the intervening space being filled by a plate 17 which is made of metal (e.g. steel) and has a smooth top surface. Above this plate and extending towards the upper part of the pin roller in one direction and some distance over the end of the slow conpassage there are three smooth walls and one not quite 1 so smooth, namely, the surface of the conveyor. Beyond the delivery endof the conveyor 2 the whole passage has smooth walls. This structure tends to operate on the moving tobacco in a manner identical with or at least analogous to that described in the above-mentioned patent and the uniformity of the tobacco mass is considerably improved in transit. It is thought that the device actually operates as follows:

As the peripheral speed of roller 10 is less than the linear speed of conveyor 2, some force appears to be necessary to cause the tobacco to enter the spaces between the pins of the roller 10, this force being compressive. It is believed to be due to the combination of momentum of the moving tobaccoand the limiting frictional force between the tobacco and conveyor 2. These are proportional to the tobacco mass. If, then, the tobacco were carried right up to the pin roller by the conveyor 2, the distribution of the tobacco on the pin roller would be similar (save for the inevitable compression) to the distribution on the slow conveyor. As, however, the exit of the passage is smooth for some distance, the direct force due to friction between the tobacco and the slow conveyor ceases as the tobacco runs on to the smooth plate 17 and this frictional force is only exerted on the tobacco in the entirely smooth part of the passage as an endwise pressure from following tobacco still on the slow conveyor. The upper conveyor 18, which preferably runs very much faster than the conveyor 2 (say two and a half times as fast), does not exert any ma- The blades are formed terial driving force on the tobacco because the conveyor 18 is smooth and at the most there is only a very slight pressure or frictional drive between it and tobacco in the passage but the drive is greatest where the tobacco is sufficiently packed to cause it to rise high in the passage.

Thus, considering the whole device, the transfer appears to be effected by end thrust (momentum plus frictional drive by following tobacco) and in consequence the tobacco is thrust towards the pins of roller by a somewhat elastic pressure. Considering the resistance offered by the pin roller as uniform, it will accept fairly closely packed tobacco relatively slowly while more sparsely packed tobacco could be thrust in more quickly. Thus, there appears to be a general closing'up of tobacco as it approaches the pin roller and naturally loose tobacco will close up more readily than tight tobacco, so a considerable improvement in uniformity of the mass results. The upper conveyor would appear to engage tightly packed parts with more frictional force than more loosely packed parts and tend to shift the tightly packed parts towards thinner areas.

In all, the device as aforesaid operates in a manner analogous to that of the apparatus described in the aforesaid specification but owing to the horizontal disposition in the present case some increase in endwise force on the moving tobacco seems to occur. At any rate the operation is decidedly beneficial.

In practice it appears to improve matters if the width of the passage is on the liberal side, that is, in the example illustrated, the width may be such that there is really room for the tobacco content of four cigarettes to lie side by side across the passage, though in fact the mass of moving tobacco only amounts to the content of three cigarettes side by side. This permits massed tobacco to move laterally under the said elastic pressure.

The plate 17 may be about the length of a cigarette.

The upper conveyor is carried on rollers 10A and 10B and driven from the latter, the roller 10A also serving to compress tobacco into the pin roller as previously mentioned.

In FIGURE 5 the slow conveyor is marked 20 and a presser roller 21 presses the tobacco into a carded or pin roller 22 having a concave shield 23. The picker roller 24 beneath the carded roller picks the tobacco therefrom and carries it around a concave 25 to discharge it on to a belt 26 with a substantial component of movement in the direction of travel of the conveyor 26.

This application is a continuation-in-part of the applicants copending US. Patent No. 2,833,290, granted May 6, 1958, on an application Serial No. 559,798, filed January 18, 1956.

What I claim as my invention and desire to secure by Letters Patent is:

A cigarette-making machine of the continuous rod type comprising a fast conveyor to receive tobacco and carry it lengthwise as a stream at high speed of the order of the speed of the cigarette rod in a cigarette-making machine, means to discharge tobacco in the form of a shower having a horizontal cross-section which is elongated in one direction, a slow conveyor arranged to move beneath the shower and transversely of the direction of elongation of the shower, and at a speed not more than one-third the speed of the said fast conveyor, to intercept the showered tobacco, a passage having smooth walls into which the tobacco is carried by the said slow conveyor, said walls comprising two smooth faced side walls and a smooth faced top wall formed by an upper conveyor moving in the same direction as the slow conveyor but at a higher speed and a smooth bottom wall provided in part by the said slow conveyor and in part by a smooth plate which forms a continuation of the bottom wall ofthe passage beyond the delivery end of the slow conveyor, transfer means to transfer tobacco from the outlet of the passage to said fast conveyor, said slow conveyor being substantially wider than the fast conveyor, and means to restrict the width of the path through which the tobacco passes in transferring from said slow conveyor to said fast conveyor, said transfer means comprising a toothed conveyor to which the tobacco is fed from the outlet of the passage, and a picker roller coacting with said toothed conveyor to remove tobacco from said toothed conveyor and to throw the tobacco downwardly on said fast conveyor.

References Cited in the file of this patent UNITED STATES PATENTS 355,590 Collins Jan. 4, 188, 2,149,925 Molins Mar. 7, 1939 2,340,914 Whitaker Feb. 8, 1944 2,671,452 Molins Mar. 9, 1954 2,830,693 Schlossmacher Apr. 15, 1958 2,833,290 Molins May 6, 1958 FOREIGN PATENTS 1,146,708 France May 27, 1957 324,930 Great Britain Feb. 5, 1930 456.865 Great Britain Nov. 17, 1936 501,518 Great Britain Feb. 28, 1939 519,470 Great Britain Mar. 26, 1940 547,760 Italy Sept. 14, 1956

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